Inhibition of electromyographic activity in human triceps surae muscles during sinusoidal rotation of the foot.

AUTOR(ES)

Freedman, W

RESUMO

Torque and electromyographic (EMG) responses to sinusoidal rotations of the foot were measured. The frequency range of the movements was 0.5 Hz to 15 Hz at amplitudes ranging between 1 and 10 degrees. At frequencies above 7 Hz, the EMG activity did not follow individual foot rotation cycles. The EMG activity was inhibited whenever the peak torque was large with respect to the first cycle peak torque. Dantrolene sodium reduced the torque developed in triceps surae, allowing the EMG activity to follow individual stretch cycles. As the drug was metabolized, the EMG activity returned to the character seen in the pre-drug control--that is, inhibition on alternate stretch cycles. It is concluded that the EMG inhibition phenomenon can be attributed in part to force receptors in muscle but that these receptors are not the sole contributors to the inhibition.

Documentos Relacionados

• Shift of activity from slow to fast muscle during voluntary lengthening contractions of the triceps surae muscles in humans.
• The role of weakness of triceps surae muscles in astasia without abasia.
• Spinal mechanisms in man contributing to reciprocal inhibition during voluntary dorsiflexion of the foot.
• Time course and extent of recovery in reinnervated motor units of cat triceps surae muscles
• Fusimotor reflexes in triceps surae muscle elicited by stretch of muscles in the contralateral hind limb of the cat.